The earlier therapeutic agent for Chronic Myelogenous Leukemia (CML, below), Imatinib mesylate (Gleevec, Korean Patent Laid-open Publication No. 1993-0021624 and Korean Patent Laid-open Publication No. 2001-0021950), has the structure of the above formula (1) wherein the amide type radical of formula (2) (n=0) is substituted at the position of R7, R4 is methyl, and R9 is methylpiperazine, and so shows restrictive therapeutic effect, low stability, and several problems in its manufacturing process. That is, since Imatinib mesylate has a high hygroscopic property, it may be easily deteriorated under the influence of the ambient moisture. Therefore, this compound should be recrystallized from a specific solvent such as methanol in order to maintain a specific crystal form, and should be used soon after its preparation. Further, this compound exhibits a therapeutic effect only on the CML and little effect on the other sites, differently from other anti cancer agents. It is synthesized in the order that 4-chloromethylbenzoic acid is combined first with N-methylpiperazine, chlorination is carried out using thionyl chloride, and the resulting side moiety is combined with the basic structure, wherein the use of thionyl chloride causes many problems such as generation of toxic gas, explosion, reduction of reaction yield, etc. Particularly, stability of the intermediate is not good to adversely affect the yield.